Originally Posted by
PerAsperaAdAstra
I know in 447's case it was complicated by the flight mode it defaulted to, trimming the stab fully nose up...
Well, to be fair the trim was only increased to full nose-up because that's what the pilot was demanding of it through the sidestick.
I was wondering if you could clarify a bit what you meant by "...why does the computer air data program attach quite so much importance to pitot static airspeed?".
If you're talking about in terms of the autopilot, it makes sense to automatically disengage it in the event of UAS condition because bad data can cause the AP to pitch the aircraft inappropriately (as in the case of Birgenair 301).
If you're talking about the FBW systems, the only thing they really lose in terms of protection is the hard protections - this is because the pilots should have full authority - introducing bad data to the systems could have unintended negative consequences.